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Publication numberUS3111695 A
Publication typeGrant
Publication dateNov 26, 1963
Filing dateSep 25, 1962
Priority dateSep 25, 1962
Publication numberUS 3111695 A, US 3111695A, US-A-3111695, US3111695 A, US3111695A
InventorsKelly Jr John M
Original AssigneeKelly Jr John M
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydroplane surfboard
US 3111695 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

Nov. 26, 1963 J. M. KELLY, JR

HYDROPLANE SURFBOARD 2 Sheets-Sheet 1 Filed Sept. 25, 1962 INVENTOR. JOHN M. AEZLZJIZ W MM ATTO/PA/[Vi Nov; 26, 1963 J. M. KELLY, JR

HYDROPLANE SURFBOARD 2 Sheets-Sheet 2 Filed Sept. 25, 1962 INVENTOR JOHN M. KELLZJ/R ATTORNEYS.

United States Patent 3,111,6fi HYDRQPLANE SURFBQARD John M. Kelly, .lr., 4117 liiaelt Point Road,

Honoiuiu, Hawaii Filed Sept. 25, 1962, Ser. No, 226,345 12 (Ilainis. (6!. 9-311?) This invention relates to a surfboard.

Most surfboards now in use are made with curved longitudinal profiles which rock about their centers of gravity in a manner to aid the rider in maintaining his fore-and-aft balance and to allow the board to approximate the curvature of the forward slope of the wave. The major disadvantage in such a rocker construction is that the board drags a quantity of water when moving directionally over and through the water thereby inhibiting its speed which limitation cannot be overcome by the rider. While drag may be desirable when the rider wishes to stall and thus ascend to a higher position on the wave, he also needs maximum speed capability to shoot the curl, i.e. to plane across the face of the wave, perhaps the most desirable riding maneuver. At any moment, the rider may need to stall again or to turn at high speed to avoid hitting another rider, to avoid rocks or to navigate wind chops or unevenness on the waves slope.

Other surfboards now designed for use exclusively in big surf, i.e., for waves above feet in height, are constructed to maximize speed by minimizing the rocker curvature and providing sharp breakaway edges around the stern. However, because of their elongated, straight and relatively flat tails which are adverse to the curved path of the surfboard when engaged in turning, these boards are inherently incapable of maneuvering at high or low speeds. Thus, these boards sacrifice maneuverability to achieve high speeds whereas the aforementioned rocker boards sacrifice speed for maneuverability.

The primary object of the invention is to overcome the aforementioned disadvantages resident in the conventional surfboards by combining in a single surfboard accessibility of both extremely high as well as low speeds and increased maneuverability at all speeds. This combination of heightened functions is accomplished by providing a planing surface and a scorpion tail which are physically differentiated by a transverse shoulder so that the rider, by body movement or shift in weight, can bring the planing surface into partial or full play or bring the drag into effect thereby achieving a wide range of speeds while maintaining maneuverability throughout.

Another object of the invention is to provide a surfboard which readily enables the rider to attain a wide range of speeds as well as accentuated maneuverability at all speeds by the functional coaction between a number of features which comprise a pianing surface and a scorpion tail which are differentiated physically by a transverse shoulder thereby creating discreetly separated bottom surfaces, the tail curving upwardly above the wake and tapering towards its tip away from the shoulder to provide a cutaway at the sides of the board in the location of the tail. The cutaway, taking advantage of the clean partition of the water from the board at the sharp breakaway edge of the transverse and vertical indentations at the bottom and sides, acts as a means to prevent the water from being sucked in around the stern and create a drag from which the rider cannot release himself. The same is true for the lift of the tail.

Another object of the invention is to provide a surfboard which enables the rider to attain a wide range of speeds, a greater maximum speed, and accentuated maneuverability, yet the board is relatively simple in design construction and easier to operate than other models.

These and other objects and features of the invention will become more apparent as the following description proceeds in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of the surfboard;

FIG. 2 is a bottom plan view thereof;

FIGS. 3, 4 and 5 are fragmentary elevational views of modified forms of shoulders;

FlG. 6 is a fragmentary top plan view of a modified form of a board at the location of the shoulder;

FIGS. 7 and 8 are fragmentary bottom views of further modified shoulder constructions;

FIGS. 9, l0 and 11 are fragmentary enlarged views of the tail end of the surfboard illustrating respectively low, partial and maximum drag;

FIG. 12 is a fragmentary vertical sectional view through the board just aft of and looking at the shoulder and illustrating one type of side edge at the planing surface; and

FIG. 13 is a view similar to FIG. 12 illustrating another type of side edge at the planing surface.

Specific reference is now made to the drawings wherein similar reference characters are used for corresponding elements throughout.

The surfboard of the instant invention is generally indicated at llll and is an elongated member capable of being fabricated of a wide variety of materials, preferably fiberglass-covered air-expanded plastic foam or balsam wood. The rider engages the upper or deck face 12 while the opposite or bottom face 14 is adapted to engage the water. The bow 16 is tapered and preferably upwardly curved to provide a scoop, whereas the stern includes an upwardly curved scorpion tail 18 having a skeg 29 depending from its bottom or tail surface 22.

The bottom face 14- includes two separate and distinct surfaces, one the tail surface '22 and the other a planing surface 24 forward thereof. These surfaces are differentiated by providing a transverse shoulder 26 formed in the bottom face, which consists of a break in the lines of the side and bottom profiles in such a manner that the tail surface 22 is elevated about the planing surface 24. The depth of the shoulder, i.e. the dis tance by which the tail surface 22 and the planing surface 24 are separated, may vary from one-eighth to four inches depending upon the body weight and preferences of I he riders as to height of the Waves to be ridden, the degree of slope of the waves at which the higher speeds are desired and the degree of braking effect desired, the depth of maximum efficiency for all desired capabilities being approximately one inch for surfboards averaging eight to ten feet in overall length. Along the longitudinal axis of the surfboard, the location of the shoulder may vary from a point approximately six inches from the stern to a point midway between the bow and stem depending upon the overall length of the board and the preferences of the riders as to maximum speed desired, degree of braking effect and sharpness of turning ability, the optimum location for desired capabilities being approximately twenty-five to thirty inches from the tip of the stern for surfboards averaging eight to ten feet in overall length.

The transverse line of juncture 28 of the planing surface 24 and the shoulder 26 is a breakaway edge which provides maximum elficiency when it is sharp, i.e., with a radius of curvature no greater than one thirty-secondth of an inch and when the inclination of the shoulder is clearly differentiated in angle from the horizontal planing surface 24. To provide simplicity of final surfacing in manufacture, as well as to reduce danger of too sharp a breakaway edge, the same may be rounded to a radius of curvature of approximately one-quarter of an inch, as shown at 30 in FIG. 3. It should be understood, however, that a sharper breakaway edge is functionally preferable due to hydrodynamic action of fluids in separating from plane surfaces. The shape of the shoulder as viewed from the side may vary from a deep recess or acute angle as shown in FIGS. 1, 2, 3, 6 and 9-H, through a substantially right angular recess 32 as shown in FIG. to a shallow recess 34 somewhat in excess of ninety degrees as shown in MG. 4-. The breakaway edge 28 may be transversely curved convexly in the direction of the stern as shown in FIG. 6, instead of straight or concave, to help ease the air around the edge of the shoulder thus enabling more effective release of the scorpion tail from the water;

The planing surface 24 functions at maximum efficiency when it is flat, both transversely and longitudinally, although it may be curved both longitudinally and transversely, the degree of longitudinal curvature being least at the shoulder and greatest where the planing surface and bow scoop merge as at 36, see FIG. 1. The side edges of the planing surface may be rounded as shown at 37 in FIG. 13 to cause the board to groove slightly into the wave but for maximum efliciency they fair down gently from the deck at an angle of approximately forty-five degrees to end in sharp side breakaway edges as shown at 39 in FIG. 12 and which are substantially parallel to the axis of the surfboard as suggested at 3? in FIG. 2. The radius of curvature of each side edge from the shoulder forward a distance approximately equal to the length of the planing surface, for maximum efficiency, should not exceed onethirty-secondth of an inch, the edge becoming rounded as it merges with the rounded sides of the board at the bow end.

The dimensions of the planing surface 24- may vary according to the overall dimensions of the board and height, weight and individual preferences of the rider but should be between seventeen and twenty-six inches transversely, and longitudinally, i.e. from the shoulder 26 to the scoop point 36, it should comprise approximately one-fifth to one-third of the total bottom surface of the board. The instant board can have a straight instead of an uplifted bow, in which case the planing surface extends from the shoulder forward to the bow extremity of the board thereby comprising a major portion of the total bottom surface.

The entire section aft of the shoulder is the scorpion tail 18 which is elevated above the planing surface in the manner indicated hereinbefore with reference to the depth of the shoulder. The scorpion tail is curved both longitudinally and transversely and upwardly from the plane of the planing surface, the upward curvature varying from slightly above the plane to a maximum of approximately eight inches measured from the tip of the tail to the extension of the plane aft of the shoulder.

It will be seen from FIG. 2 that the sides of the scorpion tail curve inwardly or taper in diminishing width fro-m the shoulder to the tip of the tail to provide a cutaway 38, which is the space between the extensions aft of the sides of the board beyond the shoulder and the sides of the tail as seen in FIG. 2. The sides of the scorpion tail at the shoulder may be sharply indented by acute angles 4t as shown in FIG. 6 or by right angles 42 as shown in FIG. 7. The sides of the scorpion tail may also be continuous with the curvature of the sides of the board, as shown at 44 in FIG. 8, though the aforementioned indentation affords *less drag and greater speed. In either case of indentation or absence thereof, the scorpion tail should lie within and not exceed the dimension across the wake area as produced by the shoulder, the planing surface and the maximum width of the surfboard forward of the shoulder.

The edges of the scorpion tail are so curved that tail surface 22 fairs gradually upward to meet the deck surface 12 in a high-drag breakaway edge comprising the periphery of tail is, the radius of curvature being not less than one-eighth of an inch at the edge itself but with maximum drag effect being achieved with a curvai ture of approximately one and one-half to two inches radius.

The skeg 24 should be long enough to extend from approximately two to twelve inches below the line extending aft of the planing surface 24 and can be positioned at any point from th shoulder to the aft end, depending upon the riders preference as to sharpness of the turning circle of the board, with maximum efiiciency being achievable for turning at all speeds when the skeg is located from about four to twelve inches measured from the aft end of the board to the aftermost trailing edge of the skeg.

In use, the rider stands on the deck of the board and by leaning his weight on the forward foot he brings the planing surface 2 5 into partial play and by taking a stance farther forward brings it into full play. By leaning back on the foot placed to the rear, he minimizes planing and brings the drag into effect. PEG. 9 shows the condition of the water 46 at low drag yielding high speed, FIG. 10 shows the condition at partial drag yielding intermediate speed and FIG. 11 shows the condition at maximum drag yielding slow speed. The scorpion tail provides a curvature adapted to the shape of the turning circle when depressed into the water thus enabling the rider to attain superior turning capability. The cutaway 38 at the tail enables the water to part cleanly from the sides of the board rather than be sucked in around the stern at all times, as on conventional boards, thereby creating drag from which the rider cannot release himself. Thus, with the instant surfboard, the rider can achieve any degree of speed while maintaining maneuverability throughout.

While preferred embodiments of the invention have been here shown and described, it will be understood that skilled artisans may make minor variations without departing from the spirit of the invention and the scope of the appended claims.

I claim:

1. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder.

2. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said forwardly extending surface having an area equal at least to one-ifth that of the total area of the bottom face.

3. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorption tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said tail curving upwardly from said shoulder to its tip.

4. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said forwardly extending portion being substantially flat and having an area equal at least to onefifth that of the total area of the bottom face, said tail curving upwardly from said shoulder to its tip.

5. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said shoulder forming a sharp breakaway edge at its juncture with said planing surface, said tail curving upwardly from said shoulder to its tip.

6. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one being substantially flat, extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said shoulder forming a sharp breakaway edge at its juncture with said planing surface, said tail curving upwardly from said shoulder to its tip, the sides of said board at the location of said planing surface fairing downwardly from the deck to terminate in sharp breakaway edges along said planing surface.

7. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said tail curving upwardly from said shoulder to its tip, and a skeg depending from said tail surface and terminating below said planing surface.

8. A surfboard comprising an elongated member having a deck and a bottom face, a vertically and transversely extending shoulder formed in the bottom face at a predetermined location dividing the same into two discreet vertically spaced continuous surfaces, the upper one extending aft of the shoulder and constituting a tail surface, the lower one being substantially fiat and extending forwardly of said shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail which curves upwardly from said shoulder to its tip and whose sides taper inwardly from said shoulder to its tip to provide a cutaway portion between the sides of said tail and extensions of the sides of the board aft of said shoulder, a skeg depending from said tail surface and terminating below said planing surface, and an upwardly curved bow portion, forwardly of said planing surface, the area of said planing surface from said shoulder to its line of merger with said bow portion comprising at least one-fifth that of the total area of said bottom face.

9. A surfboard comprising an elongated member having a deck and a bottom face, a vertically and transversely extending shoulder formed in the bottom face at a predetermined location dividing the same into two discreet vertically spaced continuous surfaces, the upper one extending aft of the shoulder and constituting a tail surface, the lower one being substantially fiat and extending forwardly of said shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail which curves upwardly from said shoulder to its tip and whose sides taper inwardly from said shoulder to its tip to provide a cutaway portion between the sides of said tail and extensions of the sides of the board aft of said shoulder, a skeg depending from said tail surface and terminating below said planing surface, and an upwardly curved bow portion forwardly of said planing surface, the area of said planing surface from said shoulder to its line of merger with said bow portion comprising at least one-fifth that of the total area of said bottom face, said shoulder forming a sharp breakaway edge at its juncture with said planing surface, the sides of said board at the location of said planing surface fairing downwardly from the deck to terminate in sharp breakaway edges along said planing surface, the tapered sides of said tail fairing upwardly from said tail surface to terminate in rounded edges along said tail.

10. A surfboard comprising an elongated member having a deck and a bottom face, a vertically and transversely extending shoulder formed in the bottom face at a predetermined location dividing the same into two discreet vertically spaced continuous surfaces, the upper one extending aft of the shoulder and constituting a tail surface, the lower one extending forwardly of said shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail which curves upwardly from said shoulder to its tip and whose sides taper inwardly from said shoulder to its tip to provide a cutaway portion between the sides of said tail and extensions of the sides of the board aft of said shoulder, a skeg depending from said tail surface and terminating below said planing surface, and an upwardly curved bow portion forwardly of said planing surface, the area of said planing surface from said shoulder to its line of merger with said bow portion comprising at least onefifth that of the total area of said bottom face, the degree of longitudinal curvature of said planing surface being least at said shoulder and greatest where it merges with said bow portion.

11. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and transversely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said shoulder forming a sharp breakaway edge at its juncture with said planing surface, said tail curving upwardly from said shoulder to its tip, the sides of said board at the location of said planing surface being rounded to cause the board to groove slightly into the wave.

'12. A surfboard comprising an elongated member having a deck and a bottom face, and a vertically and trans- T2 versely extending shoulder in the bottom face dividing said face into two discreet vertically spaced surfaces, the upper one extending aft of the shoulder to the stern and constituting a tail surface and the lower one extending forwardly of the shoulder and constituting a planing surface, the portion of the board aft of said shoulder being a scorpion tail whose sides taper inwardly towards the stern to provide a cutaway portion between the sides of the tail and extensions of the sides of the board aft of said shoulder, said shoulder forming a sharp breakaway edge at its juncture with said planing surface, said tail curving upwardly from said shoulder to its tip, said breakaway edge being transversely curved convexly towards the stern. References Cited in the file of this patent UNITED STATES PATENTS

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3015831 *Feb 20, 1958Jan 9, 1962Franke Philip RSlalom water ski
US3056148 *Jul 3, 1959Oct 2, 1962Voit Rubber CorpWater ski
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3160897 *Apr 15, 1963Dec 15, 1964Kelly Jr John MHydroplane surfboard
US3254622 *Nov 20, 1964Jun 7, 1966Bramson Clive HSurfboard propulsion device
US3337886 *Aug 6, 1965Aug 29, 1967Carl Ekstrom AdolphAsymmetrical surfboard
US3339607 *Sep 20, 1965Sep 5, 1967Howard Larry JSurfboard cover
US5944570 *May 28, 1998Aug 31, 1999Appleby; J. RandolphSurf riding craft
US6718897 *Mar 17, 2003Apr 13, 2004Joseph De BelloRideable wave propelled watersport board
US7025644 *May 24, 2004Apr 11, 2006Big River Innovations, Inc.High-performance riverboard system
US7074098Oct 26, 2005Jul 11, 2006Acosta Jr Gustavo AdolfoAquatic body board
US7823892 *Nov 2, 2010Quiksilver, Inc.Snowboard
US8408579 *Nov 21, 2007Apr 2, 2013Salomon S.A.S.Ski
US8622013Sep 16, 2009Jan 7, 2014John H. KellerSailboard step design with less ventilation and increased speed
US9242699Oct 4, 2013Jan 26, 2016K2 Keller Consulting, LlcWatercraft hull with improved lift, planing speed range, and near maximum efficiency
US20050260902 *May 24, 2004Nov 24, 2005Robert GeierHigh-performance riverboard system
US20080116662 *Nov 21, 2007May 22, 2008Salomon S.A.Ski
US20080272575 *May 4, 2007Nov 6, 2008Mike OlsonSnowboard
US20110030600 *Sep 13, 2010Feb 10, 2011Keller John HSailboard with slotted winglets
US20110197798 *Sep 16, 2009Aug 18, 2011Keller John HSailboard step design with less ventilation and increased speed
EP2337732A2 *Sep 16, 2009Jun 29, 2011John H. KellerSailboard step design with less ventilation and increased speed
WO2010033579A2Sep 16, 2009Mar 25, 2010Keller John HSailboard step design with less ventilation and increased speed
Classifications
U.S. Classification441/74, 280/609
International ClassificationB63B35/73, B63B35/79
Cooperative ClassificationB63B35/7906
European ClassificationB63B35/79C